Edit File: cpufreq.h
/* * cpufreq.h - definitions for libcpufreq * * Copyright (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef _CPUFREQ_H #define _CPUFREQ_H 1 struct cpufreq_policy { unsigned long min; unsigned long max; char *governor; }; struct cpufreq_available_governors { char *governor; struct cpufreq_available_governors *next; struct cpufreq_available_governors *first; }; struct cpufreq_available_frequencies { unsigned long frequency; struct cpufreq_available_frequencies *next; struct cpufreq_available_frequencies *first; }; struct cpufreq_affected_cpus { unsigned int cpu; struct cpufreq_affected_cpus *next; struct cpufreq_affected_cpus *first; }; struct cpufreq_stats { unsigned long frequency; unsigned long long time_in_state; struct cpufreq_stats *next; struct cpufreq_stats *first; }; #ifdef __cplusplus extern "C" { #endif /* * returns 0 if the specified CPU is present (it doesn't say * whether it is online!), and an error value if not. */ extern int cpufreq_cpu_exists(unsigned int cpu); /* determine current CPU frequency * - _kernel variant means kernel's opinion of CPU frequency * - _hardware variant means actual hardware CPU frequency, * which is only available to root. * * returns 0 on failure, else frequency in kHz. */ extern unsigned long cpufreq_get_freq_kernel(unsigned int cpu); extern unsigned long cpufreq_get_freq_hardware(unsigned int cpu); #define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu); /* determine CPU transition latency * * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds */ extern unsigned long cpufreq_get_transition_latency(unsigned int cpu); /* determine hardware CPU frequency limits * * These may be limited further by thermal, energy or other * considerations by cpufreq policy notifiers in the kernel. */ extern int cpufreq_get_hardware_limits(unsigned int cpu, unsigned long *min, unsigned long *max); /* determine CPUfreq driver used * * Remember to call cpufreq_put_driver when no longer needed * to avoid memory leakage, please. */ extern char *cpufreq_get_driver(unsigned int cpu); extern void cpufreq_put_driver(char *ptr); /* determine CPUfreq policy currently used * * Remember to call cpufreq_put_policy when no longer needed * to avoid memory leakage, please. */ extern struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu); extern void cpufreq_put_policy(struct cpufreq_policy *policy); /* determine CPUfreq governors currently available * * may be modified by modprobe'ing or rmmod'ing other governors. Please * free allocated memory by calling cpufreq_put_available_governors * after use. */ extern struct cpufreq_available_governors *cpufreq_get_available_governors(unsigned int cpu); extern void cpufreq_put_available_governors( struct cpufreq_available_governors *first); /* determine CPU frequency states available * * Only present on _some_ ->target() cpufreq drivers. For information purposes * only. Please free allocated memory by calling * cpufreq_put_available_frequencies after use. */ extern struct cpufreq_available_frequencies *cpufreq_get_available_frequencies(unsigned int cpu); extern void cpufreq_put_available_frequencies( struct cpufreq_available_frequencies *first); /* determine affected CPUs * * Remember to call cpufreq_put_affected_cpus when no longer needed * to avoid memory leakage, please. */ extern struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned int cpu); extern void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first); /* determine related CPUs * * Remember to call cpufreq_put_related_cpus when no longer needed * to avoid memory leakage, please. */ extern struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned int cpu); extern void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first); /* determine stats for cpufreq subsystem * * This is not available in all kernel versions or configurations. */ extern struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu, unsigned long long *total_time); extern void cpufreq_put_stats(struct cpufreq_stats *stats); extern unsigned long cpufreq_get_transitions(unsigned int cpu); /* set new cpufreq policy * * Tries to set the passed policy as new policy as close as possible, * but results may differ depending e.g. on governors being available. */ extern int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy); /* modify a policy by only changing min/max freq or governor * * Does not check whether result is what was intended. */ extern int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq); extern int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq); extern int cpufreq_modify_policy_governor(unsigned int cpu, char *governor); /* set a specific frequency * * Does only work if userspace governor can be used and no external * interference (other calls to this function or to set/modify_policy) * occurs. Also does not work on ->range() cpufreq drivers. */ extern int cpufreq_set_frequency(unsigned int cpu, unsigned long target_frequency); #ifdef __cplusplus } #endif #endif /* _CPUFREQ_H */